In an electric apparatus to be connected to a plurality of external apparatuses, various types of signal lines are generally wired in a high density due to a restriction in the size of a main unit of the apparatus. Particularly, in a train-information transmission/reception apparatus, which is one of the electric apparatuses incorporated in a railway vehicle, a plurality of signal lines are combined in a single connector so as to transmit various signals ranging from an analogue signal to a high-speed digital signal to and from a plurality of apparatuses having different functions. Therefore, a plurality of types of signals may exist in a mixed manner in a single connector.
A shielded cable, which is one of the media for transmitting a signal, is mainly configured with a conductor for transmitting signals and a shield (a shielded layer) covering the conductor. For example, in a conventional technique disclosed in Patent Literature 1, the following methods have been adopted to ground the shielded layer to a frame ground of the train-information transmission/reception apparatus.
A first method includes processing a shielded layer in a pigtail shape at a position farthest from a train-information transmission/reception apparatus (for example, a connector to be arranged in a connection portion between vehicles) and grounding the pigtail to a vehicle body. A second method includes processing a shielded layer in a pigtail shape near a train-information transmission/reception apparatus and providing a connector pin at an end portion of the pigtail. In this method, when the connector is connected to the train-information transmission/reception apparatus, the ground is secured via the connector pin, a GND line mounted to a substrate of the train-information transmission/reception apparatus, and a frame ground of the train-information transmission/reception apparatus.